Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758059AbZIPI6g (ORCPT ); Wed, 16 Sep 2009 04:58:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757707AbZIPI6f (ORCPT ); Wed, 16 Sep 2009 04:58:35 -0400 Received: from mail-ew0-f206.google.com ([209.85.219.206]:60821 "EHLO mail-ew0-f206.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757605AbZIPI6e (ORCPT ); Wed, 16 Sep 2009 04:58:34 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=YoYaZ0D7KNIN0tVWAJZS+096pRdbuOYvi1fgFphJtxjz/nJTwlpkc9WG1WYQ8GG4Mt ozQr2B+KB/l9OTqm4dWCxqwv7um1BTCmZZrfET3K7yJHTRXdahmsIcUp4aola4rRpvOg lL54F8DtHxd7rePNhxcRCPNXeZ6giEAzOFkDw= Date: Wed, 16 Sep 2009 12:58:35 +0400 From: Cyrill Gorcunov To: Sheng Yang Cc: Keir Fraser , Jeremy Fitzhardinge , Jun Nakajima , Eddie Dong , linux-kernel@vger.kernel.org, xen-devel Subject: Re: [RFC][PATCH 08/10] x86: Don't ack_APIC_irq() if lapic is disabled in GENERIC_INTERRUPT_VECTOR handler Message-ID: <20090916085835.GE5094@lenovo> References: <1253090551-7969-1-git-send-email-sheng@linux.intel.com> <1253090551-7969-9-git-send-email-sheng@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1253090551-7969-9-git-send-email-sheng@linux.intel.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1137 Lines: 36 [Sheng Yang - Wed, Sep 16, 2009 at 04:42:29PM +0800] | Xen hybrid guest don't use lapic, but smp_generic_interrupt() assume all it's | caller using lapic. | | Signed-off-by: Sheng Yang | --- | arch/x86/kernel/irq.c | 3 ++- | 1 files changed, 2 insertions(+), 1 deletions(-) | | diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c | index c3fe010..a887d25 100644 | --- a/arch/x86/kernel/irq.c | +++ b/arch/x86/kernel/irq.c | @@ -236,7 +236,8 @@ void smp_generic_interrupt(struct pt_regs *regs) | { | struct pt_regs *old_regs = set_irq_regs(regs); | | - ack_APIC_irq(); | + if (!disable_apic) | + ack_APIC_irq(); | | exit_idle(); Hi Sheng, is there was some problem with it? I'm asking you because if disable_apic=1 then any apic write/read operations become NOPs. So I don't see how it may hurt. But I could be missing something. -- Cyrill -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/